US8603650B2 - Perpendicular magnetic recording disk and manufacturing method thereof - Google Patents

Perpendicular magnetic recording disk and manufacturing method thereof Download PDF

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US8603650B2
US8603650B2 US10/576,755 US57675505A US8603650B2 US 8603650 B2 US8603650 B2 US 8603650B2 US 57675505 A US57675505 A US 57675505A US 8603650 B2 US8603650 B2 US 8603650B2
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magnetic recording
perpendicular magnetic
ferromagnetic
ferromagnetic layer
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US20070148499A1 (en
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Yoshiaki Sonobe
Teiichiro Umezawa
Chikara Takasu
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Western Digital Technologies Inc
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WD Media Singapore Pte Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F10/00—Thin magnetic films, e.g. of one-domain structure
    • H01F10/007—Thin magnetic films, e.g. of one-domain structure ultrathin or granular films
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y25/00—Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/64—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent
    • G11B5/66—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent the record carriers consisting of several layers
    • G11B5/676—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent the record carriers consisting of several layers having magnetic layers separated by a nonmagnetic layer, e.g. antiferromagnetic layer, Cu layer or coupling layer
    • G11B5/678—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent the record carriers consisting of several layers having magnetic layers separated by a nonmagnetic layer, e.g. antiferromagnetic layer, Cu layer or coupling layer having three or more magnetic layers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
    • G11B5/851—Coating a support with a magnetic layer by sputtering
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B2005/0002—Special dispositions or recording techniques
    • G11B2005/0026—Pulse recording
    • G11B2005/0029—Pulse recording using magnetisation components of the recording layer disposed mainly perpendicularly to the record carrier surface
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F10/00—Thin magnetic films, e.g. of one-domain structure
    • H01F10/08—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers
    • H01F10/10—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition
    • H01F10/12—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition being metals or alloys
    • H01F10/16—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition being metals or alloys containing cobalt
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/14—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates
    • H01F41/18—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates by cathode sputtering

Definitions

  • This invention relates to a perpendicular magnetic recording disk adapted to be mounted in a perpendicular magnetic recording type HDD (hard disk drive) or the like.
  • the magnetic disk of the perpendicular magnetic recording type has been proposed in recent years.
  • the easy magnetization axis of a magnetic recording layer is adjusted so as to be oriented in a direction perpendicular to the surface of a substrate.
  • the perpendicular magnetic recording type can suppress the thermal fluctuation phenomenon and thus is suitable for increasing the recording density.
  • Patent Document 1 discloses a technique about a perpendicular magnetic recording medium having an underlayer, a Co-based perpendicular magnetic recording layer, and a protective layer that are formed on a substrate in the order named.
  • Patent Document 2 discloses a perpendicular magnetic recording medium having a structure where an exchange-coupled artificial lattice film continuous layer (exchange-coupled layer) is adhered to a granular recording layer.
  • the recording density of a magnetic disk is improved mainly by reducing noise in a magnetization transition region of a magnetic recording layer.
  • noise reduction it is necessary to improve the crystal orientation of the magnetic recording layer or reduce the crystal grain size and the magnitude of magnetic interaction. That is, in order to increase the recording density of the medium, it is desirable to equalize and reduce the crystal grain size of the magnetic recording layer and, further, to provide a segregated state where individual magnetic crystal grains are magnetically segregated and, for that, it is necessary to properly control a fine structure of the magnetic recording layer.
  • the Co-based perpendicular magnetic recording layer disclosed in Patent Document 1 has a high coercive force Hc and can cause a magnetization reversal producing magnetic field Hn to be a small value less than zero and, therefore, resistance against thermal fluctuation can be improved and a high S/N ratio can be achieved, which is thus preferable.
  • an element such as Cr to be contained in such a perpendicular magnetic recording layer, Cr can be segregated at grain boundary portions of the magnetic crystal grains to block exchange interaction between the magnetic crystal grains, thereby contributing to increasing the recording density.
  • the oxide such as SiO 2 or O is segregated at the grain boundaries to reduce the magnetic interaction between the crystal grains of the magnetic recording layer.
  • the oxide such as SiO 2 or O is added to the CoPt-based perpendicular magnetic recording layer.
  • the crystal grain size can be reduced.
  • the crystal grain size and the magnitude of the magnetic interaction are affected by the thickness of SiO 2 layers segregated at the grain boundaries or the crystal grain size of the underlayer.
  • FIG. 6 shows a relationship between a coercive force Hc and a SNR when increasing the amount of SiO 2 . According to FIG. 6 , the Hc decreases as the amount of SiO 2 increases. It is considered that the thermal stability degrades and the DC noise increases due to reduction in coercive force Hc.
  • the present inventors have found that as the amount of SiO 2 increases, the SNR (SN Ratio: hereinafter also referred to as SN) becomes better due to size reduction (see FIG. 6 ).
  • the axis of ordinates showing the SNR graduates differences from a reference value properly defined.
  • SiO 2 and SN it is understood that when SiO 2 is added in an amount of 6 at % or more, the SN is rapidly improved. Therefore, a medium is desirable that maintains the thermal stability and, further, is added with SiO 2 in an amount of 6 at % or more where the SN becomes excellent.
  • This invention solves such conventional and new problems and has an object to provide a perpendicular magnetic recording disk that can contribute to increasing the recording density by improving the S/N ratio in high density recording without causing an increase in DC noise, degradation in thermal stability, and degradation in recording capability, and a method of manufacturing such a disk.
  • this invention has the following structures.
  • a perpendicular magnetic recording disk for use in perpendicular magnetic recording characterized by comprising a substrate, a ferromagnetic layer formed on the substrate, having a granular structure, and containing an oxide, silicon (Si), or an oxide of silicon (Si), and a stacked layer formed on the ferromagnetic layer and having a first layer containing cobalt (Co) or a Co alloy and a second layer containing palladium (Pd) or platinum (Pt).
  • (Structure 2) A perpendicular magnetic recording disk according to Structure 1, characterized in that the ferromagnetic layer has crystal gains mainly made of cobalt (Co) and grain boundary portions mainly made of the oxide, the silicon (Si), or the oxide of silicon (Si).
  • (Structure 3) A perpendicular magnetic recording disk according to Structure 1 or 2, characterized in that the content of the silicon (Si) in the ferromagnetic layer is 6 at % or more.
  • (Structure 4) A perpendicular magnetic recording disk according to Structure 1 or 2, characterized in that the content of the silicon (Si) in the ferromagnetic layer is 8 at % to 15 at %.
  • Structure 5 A perpendicular magnetic recording disk according to any of Structures 1 to 4, characterized in that a spacer layer is provided between the ferromagnetic layer and the stacked layer.
  • (Structure 6) A method of manufacturing a perpendicular magnetic recording disk for use in perpendicular magnetic recording and having at least a magnetic recording layer on a substrate, the method characterized by, in a step of forming the magnetic recording layer comprising, on the substrate, a ferromagnetic layer of a granular structure containing silicon (Si) or an oxide of silicon (Si) between crystal grains containing cobalt (Co) and a stacked layer having a first layer containing Co or a Co alloy and a second layer containing palladium (Pd) or platinum (Pt), forming the ferromagnetic layer on the substrate by sputtering in an argon gas atmosphere and then forming the stacked layer by sputtering in an argon gas atmosphere at a gas pressure lower than a gas pressure used when forming the ferromagnetic layer.
  • the magnetic recording layer includes at least the ferromagnetic layer formed on the substrate, having the granular structure, and containing an oxide, silicon (Si), or an oxide of silicon (Si), and the stacked layer formed on the ferromagnetic layer and having the first layer containing Co or a Co alloy and the second layer containing Pd or Pt.
  • Co-based magnetic material forming the ferromagnetic layer particularly a CoPt-based or CoPtCr-based magnetic material is preferable.
  • the CoPt-based or CoPtCr-based magnetic material has a high coercive force Hc and can cause a magnetization reversal producing magnetic field Hn to be a small value less than zero and, therefore, resistance against thermal fluctuation can be improved and a high S/N ratio can be achieved, which is thus preferable.
  • Si silicon
  • Si an element such as silicon (Si) or an oxide thereof to be contained in the CoPt-based or CoPtCr-based magnetic material
  • Si or the like or the oxide thereof can be segregated at grain boundary portions of the magnetic crystal grains to reduce the exchange interaction between the magnetic crystal grains, thereby reducing the medium noise and improving the S/N ratio in high density recording.
  • Si may be added to the CoPt-based or CoPtCr-based magnetic material not only alone, but also as an oxide or Si oxide such as SiO 2 .
  • Si is added as the Si oxide such as SiO 2
  • the Si oxide is segregated at the grain boundaries to reduce the magnetic interaction between the crystal grains of the magnetic recording layer, thereby reducing the medium noise and improving the S/N ratio in high density recording.
  • the crystal grain size can be reduced.
  • the adding amount of Si or the Si oxide is large, the crystal grains become too small, so that the thermal fluctuation increases. Therefore, for example, the adding amount of the Si oxide is suppressed to 5 at % or less conventionally. Accordingly, there is inevitably a limit to the increase in recording density.
  • the degradation of thermal stability can be prevented by the ferromagnetic layer containing the oxide, silicon (Si), or the silicon (Si) oxide and the stacked layer formed on the ferromagnetic layer and having the first layer containing Co or the Co alloy and the second layer containing Pd or Pt, thereby contributing to increasing the recording density without causing the degradation of thermal stability.
  • the ferromagnetic layer has the crystal gains mainly made of Co and the grain boundary portions mainly made of the oxide, silicon (Si), or the silicon (Si) oxide. It becomes possible to magnetically shield between the size-reduced crystal grains.
  • the content of silicon (Si) in the ferromagnetic layer is 6 at % or more, and more preferably 8 at % to 15 at %.
  • the content of silicon (Si) in the ferromagnetic layer is 6 at % or more, the SN is rapidly improved.
  • 8 at % to 15 at % is preferable for the following reason.
  • the content is less than 8 at %, the effect of reducing the medium noise is small and, further, the S/N ratio in high density recording cannot be improved sufficiently.
  • the content is greater than 15 at %, the perpendicular magnetic anisotropy starts to degrade and, following it, there occurs the degradation of thermal stability in high density recording or the increase in DC noise.
  • the ferromagnetic layer has the granular structure containing Si or the oxide thereof between the magnetic crystal grains containing Co.
  • the thickness of the ferromagnetic layer is preferably 20 nm or less. Desirably, the range of 8 to 16 nm is preferable.
  • the stacked layer is adjacent to the ferromagnetic layer or through the spacer layer therebetween.
  • the stacked layer is magnetically coupled to the ferromagnetic layer and functions to align the easy magnetization axes of the respective layers substantially in the same direction.
  • crystal grains are magnetically coupled to each other.
  • the stacked layer is preferably made of alternate-layered films of cobalt (Co) or an alloy thereof and palladium (Pd) or alternate-layered films of cobalt (Co) or an alloy thereof and platinum (Pt). Since the alternate-layered films made of such materials have large magnetic Ku, the domain wall width in the stacked layer can be reduced.
  • the thickness thereof is preferably 1 to 8 nm.
  • the thickness of the ferromagnetic layer is A and the thickness of the exchange energy control layer is B
  • A/B ratio of A to B
  • the spacer layer is preferably provided between the ferromagnetic layer and the stacked layer.
  • the exchange coupling between the ferromagnetic layer and the stacked layer can be suitably controlled.
  • the spacer layer use is preferably made of, for example, a Pd layer or a Pt layer depending on the stacked layer.
  • the Pd layer is also used as the spacer layer. This is because it is economically preferable to use the same composition in terms of the condition of a manufacturing apparatus.
  • the thickness of the spacer layer is preferably 2 nm or less and desirably in the range of 0.5 to 1.5 nm.
  • the ferromagnetic layer and the stacked layer are disposed adjacent to each other or through the spacer layer interposed therebetween and, in view of HDI (Head Disk Interface), it is preferable to dispose the stacked layer above the ferromagnetic layer as seen from the substrate.
  • the ferromagnetic layer is not limited to the single layer, but may be composed of a plurality of layers. In this case, Co-based magnetic layers containing Si or the Si oxide may be combined with each other, or a Co-based magnetic layer containing Si or the Si oxide and a Co-based magnetic layer containing no Si or Si oxide may be combined with each other. Note that it is preferable to dispose the Co-based magnetic layer containing Si or the Si oxide on the side adjacent to the stacked layer.
  • the perpendicular magnetic recording layer of this invention is preferably formed by the sputtering method. Particularly, the DC magnetron sputtering method is preferable because uniform film formation is enabled.
  • the perpendicular magnetic recording layer composed of the ferromagnetic layer and the stacked layer on the substrate it is desirable to form the ferromagnetic layer on the substrate by sputtering in the argon gas atmosphere and then to form the stacked layer by sputtering in the argon gas atmosphere at the gas pressure lower than that used when forming the ferromagnetic layer. It is necessary that the ferromagnetic layer be formed at high gas pressure. The reason is that the magnetic grain size in the ferromagnetic layer can be diminished in order to reduce the medium noise and, further, Si or the Si oxide can be segregated in a uniform thickness between the magnetic crystal grains containing Co at the grain boundaries.
  • the stacked layer is required to be magnetically uniform for fixing domain walls (magnetization transition points) anywhere by pinning force from the magnetic grains of the ferromagnetic layer, i.e. for allowing the domain walls to freely move unless there is the ferromagnetic layer adjacent to the stacked layer, and it is preferable to form the stacked layer at low gas pressure for that purpose.
  • the stacked layer is preferably formed by sputtering at a gas temperature, for example, in the range of 1 to 10 mTorr.
  • the ferromagnetic layer is preferably formed by sputtering at a gas temperature of 30 mTorr or more.
  • the perpendicular magnetic recording disk of this invention has at least the foregoing perpendicular magnetic recording layer on the substrate and preferably has various functional layers in addition thereto.
  • a soft magnetic layer may be provided on the substrate for suitably adjusting a magnetic circuit of the perpendicular magnetic recording layer.
  • the soft magnetic layer is not particularly limited as long as it is made of a magnetic body that exhibits soft magnetic properties and, for example, preferably has as a magnetic property a coercive force of 0.01 to 80 oersteds and more preferably 0.01 to 50 oersteds. Further, it preferably has as a magnetic property a saturation magnetic flux density (Bs) of 500 emu/cc to 1920 emu/cc.
  • an Fe-based material As a material of the soft magnetic layer, there can be cited an Fe-based material, a Co-based material, or the like.
  • an Fe-based soft magnetic material such as FeTaC-based alloy, FeTaN-based alloy, FeNi-based alloy, FeCoB-based alloy, or FeCo-based alloy, a Co-based soft magnetic material such as CoTaZr-based alloy or CoNbZr-based alloy, an FeCo-based alloy soft magnetic material, or the like.
  • the thickness of the soft magnetic layer is preferably 30 nm to 1000 nm and desirably 50 nm to 200 nm.
  • the thickness of the soft magnetic layer is preferably 30 nm to 1000 nm and desirably 50 nm to 200 nm.
  • it is less than 30 nm there is a case where it becomes difficult to form a suitable magnetic circuit between magnetic head—perpendicular magnetic recording layer—soft magnetic layer
  • a nonmagnetic underlayer is preferably provided on the substrate for orienting the crystals of the perpendicular magnetic recording layer in a direction perpendicular to the substrate surface.
  • a Ti-based alloy is preferable as a material of the nonmagnetic underlayer.
  • the Ti-based alloy well serves to control crystal axes (c-axes) of the CoPt-based perpendicular magnetic recording layer having the hcp crystal structure to be oriented in the perpendicular direction.
  • the nonmagnetic underlayer made of the Ti-based alloy there can be cited, other than Ti, a TiCr-based alloy, a TiCo-based alloy, or the like.
  • the thickness of such a nonmagnetic underlayer is preferably 2 nm to 30 nm.
  • the thickness of the underlayer is less than 2 nm, the control of the crystal axes of the perpendicular magnetic recording layer is insufficient, while, when it exceeds 30 nm, the size of the magnetic crystal grains forming the perpendicular magnetic recording layer is enlarged to increase the noise, which is thus not preferable.
  • the substrate when magnetic field annealing is necessary for controlling magnetic domains of the soft magnetic layer, the substrate is preferably made of a glass. Since the glass substrate is excellent in heat resistance, the heating temperature of the substrate can be set high.
  • the glass for the substrate there can be cited an aluminosilicate glass, an aluminoborosilicate glass, a soda lime glass, or the like. Among them, the aluminosilicate glass is preferable. Further, an amorphous glass or a crystallized glass can be used.
  • the substrate is preferably made of the amorphous glass. When a chemically strengthened glass is used, the rigidity is high, which is thus preferable.
  • the surface roughness of the main surface of the substrate is preferably 6 nm or less in Rmax and 0.6 nm or less in Ra.
  • an adhesion layer between the substrate and the soft magnetic layer.
  • the adhesion layer By forming the adhesion layer, the adhesion between the substrate and the soft magnetic layer can be improved and, therefore, it is possible to prevent stripping of the soft magnetic layer.
  • a material of the adhesion layer use can be made of, for example, a Ti-containing material.
  • the thickness of the adhesion layer is preferably set to 1 nm to 50 nm.
  • a protective layer on the perpendicular magnetic recording layer. By providing the protective layer, it is possible to protect the surface of the magnetic disk from the magnetic recording head flying over the magnetic disk.
  • a material of the protective layer for example, a carbon-based protective layer is preferable.
  • the thickness of the protective layer is preferably about 3 nm to 7 nm.
  • a lubricating layer on the protective layer.
  • PFPE perfluoropolyether
  • the thickness of the lubricating layer is preferably about 0.5 nm to 1.5 nm.
  • the soft magnetic layer, the underlayer, the adhesion layer, and the protective layer be also formed by the sputtering method.
  • the DC magnetron sputtering method is preferable because uniform film formation is enabled. It is also preferable to use the in-line type film forming method.
  • the lubricating layer is preferably formed, for example, by the dip coating method.
  • a perpendicular magnetic recording disk that can contribute to increasing the recording density by improving the S/N ratio in high density recording without causing an increase in DC noise, degradation in thermal stability, and degradation in recording capability, and a method of manufacturing such a disk.
  • FIG. 1 shows one embodiment of a perpendicular magnetic recording disk according to this invention.
  • the embodiment of the perpendicular magnetic recording disk 10 of this invention has a structure in which an adhesion layer 2 , a soft magnetic layer 3 , a first underlayer 4 a , a second underlayer 4 b , a ferromagnetic layer 5 , a spacer layer 6 , a stacked layer 7 , a carbon-based protective layer 8 , and a lubricating layer 9 are provided on a glass substrate 1 in the order named.
  • this invention will be described in detail by giving examples and comparative examples.
  • An amorphous aluminosilicate glass was molded into a disk shape by direct press, thereby producing a glass disk.
  • This glass disk was ground, polished, and chemically strengthened in order, thereby obtaining a smooth nonmagnetic glass substrate 1 in the form of a chemically strengthened glass disk.
  • the disk diameter was 65 mm.
  • the surface roughness of the main surface of the glass substrate 1 was measured by an AFM (atomic force microscope) and it was a smooth surface shape with Rmax being 4.8 nm and Ra being 0.42 nm. Rmax and Ra follow Japanese Industrial Standard (JIS).
  • an adhesion layer 2 and a soft magnetic layer 3 were formed in order on the obtained glass substrate 1 in an Ar atmosphere according to the DC magnetron sputtering method.
  • the adhesion layer 2 was formed by the use of a Ti target so as to be a Ti layer having a thickness of 20 nm.
  • the soft magnetic layer 3 was formed by the use of a CoTaZr target so as to be an amorphous CoTaZr (Co:88 at %, Ta:7.0 at %, Zr:4.9 at %) layer having a thickness of 200 nm.
  • the substrate for a perpendicular magnetic recording disk thus finished with the film formation up to the soft magnetic layer 3 was removed from the film forming apparatus.
  • the surface roughness of the obtained perpendicular magnetic recording disk substrate finished with the film formation up to the soft magnetic layer 3 was measured by the AFM in the same manner and it was a smooth surface shape with Rmax being 5.1 nm and Ra being 0.48 nm.
  • the magnetic properties of the substrate were measured by a VSM (Vibrating Sample Magnetometer). As a result, the coercive force (Hc) was 2 Oe and the saturation magnetic flux density was 810 emu/cc, thus showing suitable soft magnetic properties.
  • underlayers and a perpendicular magnetic recording layer are formed on the soft magnetic layer 3 having the smooth surface shape with Rmax being 5.5 nm or less and/or Ra being 0.5 nm or less, it is suitable for reducing noise. Then, by the use of an evacuated single-wafer stationary facing type film forming apparatus, a first underlayer 4 a , a second underlayer 4 b , a ferromagnetic layer 5 , a spacer layer 6 , a stacked layer 7 , and a carbon-based protective layer 8 were formed in order on the obtained substrate in an Ar atmosphere according to the DC magnetron sputtering method.
  • the first underlayer 4 a made of amorphous NiTa (Ni:45 at %, Ta:55 at %) and having a thickness of 10 nm and the second underlayer 4 b made of Ru and having a thickness of 30 nm were formed.
  • two layers each made of Ru may be formed instead. That is, by forming the upper-layer side Ru at a gas pressure of the Ar gas higher than that used when forming the lower-layer side Ru, the crystal orientation can be improved.
  • the ferromagnetic layer 5 having a hcp crystal structure was formed to a thickness of 15 nm.
  • the composition of the target for forming the ferromagnetic layer 5 was Co:62 at %, Cr:10 at %, Pt:16 at %, SiO 2 :12 at %.
  • the ferromagnetic layer 5 was formed at a gas pressure of 30 mTorr.
  • the spacer layer 6 made of Pd and having a thickness of 0.9 nm was formed.
  • the stacked layer 7 in the form of alternate-layered films of CoB and Pd was formed.
  • CoB was first formed into a film of 0.3 nm and, thereon, Pd was formed into a film of 0.9 nm. Accordingly, the total thickness of the stacked layer 6 was 1.2 nm.
  • the stacked layer 7 was formed at a gas pressure of 10 mTorr lower than that used when forming the ferromagnetic layer 5 .
  • the carbon-based protective layer 8 made of hydrogenated carbon was formed.
  • the thickness of the carbon-based protective layer 8 was 4.5 nm. Since the film hardness is improved in the form of hydrogenated carbon, it is possible to protect the perpendicular magnetic recording layer against an impact from a magnetic head.
  • a lubricating layer 9 made of PFPE (perfluoropolyether) was formed by the dip coating method. The thickness of the lubricating layer 9 was 1 nm.
  • the surface roughness of the obtained perpendicular magnetic recording disk was measured by the AFM in the same manner and it was a smooth surface shape with Rmax being 4.53 nm and Ra being 0.40 nm.
  • Rmax being 4.53 nm
  • Ra being 0.40 nm.
  • the orientation of the perpendicular magnetic recording layer (the ferromagnetic layer 5 , the spacer layer 6 , and the stacked layer 7 will be collectively called the perpendicular magnetic recording layer and the same shall apply hereinafter) in the obtained perpendicular magnetic recording disk was analyzed by the X-ray diffraction method and the c-axis of the hcp (hexagonal close-packed) crystal structure was oriented in a direction perpendicular to the disk surface. Further, the ferromagnetic layer 5 in the obtained perpendicular magnetic recording disk was analyzed in detail by the use of a transmission electron microscope (TEM) and it had a granular structure.
  • TEM transmission electron microscope
  • the stacked layer 7 being the layer above the ferromagnetic layer 5 having the granular structure was analyzed in detail by the use of the TEM and it did not have a granular structure. This represents that the stacked layer 7 has a structure being substantially continuous magnetically. That is, this represents that the magnetic grains of the ferromagnetic layer 5 of the granular structure are magnetically coupled through the stacked layer 7 . It is considered that this improves the thermal stability.
  • a perpendicular magnetic recording disk was obtained in the same manner as in Example 1 except that the stacked layer 7 in Example 1 was changed to alternate-layered films of two cycles of CoB and Pd (Example 2).
  • the total thickness of the stacked layer 7 in the perpendicular magnetic recording disk of this example was 2.4 nm.
  • the orientation of a perpendicular magnetic recording layer in the obtained perpendicular magnetic recording disk was analyzed by the X-ray diffraction method and, like in Example 1, the c-axis of a hcp (hexagonal close-packed) crystal structure was oriented in a direction perpendicular to the disk surface.
  • a ferromagnetic layer 5 in the obtained perpendicular magnetic recording disk was analyzed in detail by the use of the transmission electron microscope (TEM) and it had a granular structure like in Example 1. Specifically, it was confirmed that grain boundary portions made of Si oxide were formed between crystal grains of the hcp crystal structure containing Co.
  • a perpendicular magnetic recording disk was obtained in the same manner as in Example 1 except that the stacked layer 7 in Example 1 was changed to alternate-layered films of five cycles of CoB and Pd (Example 3).
  • the total thickness of the stacked layer 7 in the perpendicular magnetic recording disk of this example was 6.0 nm.
  • the orientation of a perpendicular magnetic recording layer in the obtained perpendicular magnetic recording disk was analyzed by the X-ray diffraction method and, like in Example 1, the c-axis of a hcp (hexagonal close-packed) crystal structure was oriented in a direction perpendicular to the disk surface.
  • a ferromagnetic layer 5 in the obtained perpendicular magnetic recording disk was analyzed in detail by the use of the transmission electron microscope (TEM) and it had a granular structure like in Example 1. Specifically, it was confirmed that grain boundary portions made of Si oxide were formed between crystal grains of the hcp crystal structure containing Co.
  • Example 1 by the use of a hard magnetic target made of CoCrPt and SiO 2 (Co:62 at %, Cr:10 at %, Pt: 16 at %, SiO 2 :12 at %), a ferromagnetic layer 5 was formed to a thickness of 15 nm. Then, on this ferromagnetic layer 5 , a carbon-based protective layer 8 and a lubricating layer 9 were formed without forming a spacer layer 6 and a stacked layer 7 . Except this point, a perpendicular magnetic recording disk was obtained in the same manner as in Example 1.
  • the surface roughness of the obtained perpendicular magnetic recording disk was measured by the AFM and it was a surface shape with Rmax being 6.26 nm and Ra being 0.48 nm. This is rougher as compared with the foregoing perpendicular magnetic recording disk formed with the spacer layer 6 and the stacked layer 7 . Further, the orientation of the ferromagnetic layer 5 in the obtained perpendicular magnetic recording disk was analyzed by the X-ray diffraction method and the c-axis of a hcp (hexagonal close-packed) crystal structure was oriented in a direction perpendicular to the disk surface.
  • the ferromagnetic layer 5 in the obtained perpendicular magnetic recording disk was analyzed in detail by the use of the transmission electron microscope (TEM) and it had a granular structure. Specifically, it was confirmed that grain boundary portions made of Si oxide were formed between crystal grains of the hcp crystal structure containing Co.
  • Example 1 by the use of a hard magnetic target made of CoCrPt (Co:70 at %, Cr:18 at %, Pt:12 at %), a ferromagnetic layer 5 was formed to a thickness of 15 nm. Except this point, a perpendicular magnetic recording disk was obtained in the same manner as in Example 1. The orientation of a perpendicular magnetic recording layer in the obtained perpendicular magnetic recording disk was analyzed by the X-ray diffraction method and the c-axis of a hcp (hexagonal close-packed) crystal structure was oriented in a direction perpendicular to the disk surface.
  • FIG. 2 shows a magnetization reversal nucleus producing magnetic field (Hn) and a saturation magnetic field (Hs) in an MH curve.
  • the magnetization reversal nucleus producing magnetic field (Hn) is a numerical value at a point on the axis of abscissas corresponding to a point of intersection between a tangent of a line showing saturation magnetization and a tangent of an oblique line.
  • the saturation magnetic field (Hs) is a numerical value at a point on the axis of abscissas corresponding to a point of intersection of a hysteresis loop. From FIG. 3 , it is understood that the magnetization reversal nucleus producing magnetic field (Hn) increases while the saturation magnetic field (Hs) decreases due to the increase in thickness of the stacked layer.
  • the magnetization reversal nucleus producing magnetic field (Hn) measured by the polar Kerr loop tracer increases by about 100 to 1600 oersteds (Oe) as compared with the conventional type perpendicular magnetic recording disk as shown in Patent Document 2 wherein, like Comparative Example 2, the perpendicular magnetic recording layer has the layered structure of the ferromagnetic layer 5 , the spacer layer 6 , and the stacked layer 7 but the magnetic recording layer does not contain Si or Si oxide.
  • the overwrite properties are largely improved by 1.5 to 2.1 dB in Example 1, 6.6 to 7.2 dB in Example 2, and 21.3 to 21.9 dB in Example 3 as compared with Comparative Examples 1 and 2.
  • S/N(DC) is largely improved by 1.0 to 1.8 dB in Example 1, 3.1 to 3.9 dB in Example 2, and 7.0 to 7.8 dB in Example 3 as compared with Comparative Examples 1 and 2.
  • S/N(MF) is improved by 0.5 dB in Example 1, 0.7 dB in Example 2, and 2.0 dB in Example 3 as compared with Comparative Example 2 and improved by 7.0 dB in Example 1, 7.2 dB in Example 2, and 8.5 dB in Example 3 as compared with Comparative Example 1.
  • an improvement by about one to two digits was obtained. This value represents that this invention can achieve a recording density about two to three times larger than that of the conventional type mediums like Comparative Examples 1 and 2.
  • the electromagnetic conversion properties were measured in the following manner.
  • the measurement was carried out by the use of a R/W analyzer (DECO) and a magnetic head for a perpendicular magnetic recording system having a SPT element on the recording side and a GMR element on the reproducing side.
  • the flying height of the magnetic head was 10 nm.
  • S/N(DC) was calculated by recording a carrier signal on the perpendicular magnetic recording medium at 24F recording density (40 kfci) and then observing medium noise from a DC frequency range to a frequency range 1.2 times 1F by the use of a spectrum analyzer.
  • S/N(MF) was calculated by recording a carrier signal on the perpendicular magnetic recording medium at 2F recording density (480 kfci) and then observing medium noise from the DC frequency range to the frequency range 1.2 times 1F by the use of the spectrum analyzer.
  • the overwrite property was derived by recording a carrier signal on the perpendicular magnetic recording medium at 24F (40 kfci) recording density, then overwriting a carrier at 1F recording density (960 kfci), and then measuring a carrier reproduction output at the original 24F (40 kfci) recording density and a remaining reproduction output of a 12F carrier after the 1F overwriting.
  • Example 3 the medium having the alternate-layered films of five cycles of CoB and Pd as the stacked layer 7
  • Comparative Example 1 the medium without the spacer layer 6 and the stacked layer 7 .
  • the evaluation of the thermal stability was carried out by recording a signal on the magnetic disk and then confirming a reproduction output after the lapse of a predetermined time. Accordingly, the thermal stability was evaluated by measuring the decay rate of the signal with the lapse of time.
  • FIG. 4 is a diagram showing a relationship between an elapsed time and a ratio to a reproduction output immediately after recording, wherein the results of Example 3 according to this invention are plotted by ⁇ and the results of Comparative Example 1 are plotted by ⁇ .
  • the reproduction output weakens as the time elapses in the case of the magnetic disk of Comparative Example 1 being the medium without the spacer layer 6 and the stacked layer 7 .
  • the reproduction output hardly weakens and thus the thermal stability is excellent in the case of the magnetic disk of Example 3 according to this invention.
  • ⁇ Hc was measured in order to examine as to what caused the improvement in SN as described above.
  • ⁇ Hc is a difference between a value of H at a half position of saturation magnetization Ms in a minor loop and a value of H at a half position of saturation magnetization Ms in a hysteresis curve.
  • a value standardized by Hc is used as an index for observing dispersion of coercive force of magnetic grains.
  • the minor loop represents a curve describing a minor loop by causing a magnetic field to be zero before saturation.
  • FIG. 5 (a) and FIG. 5 , (b), average lines are adopted from among curves repeatedly described a plurality of times.
  • FIG. 5 , (a) and FIG. 5 , (b) respectively describe minor loops and hysteresis curves of the magnetic disk according to Comparative Example 1 and the magnetic disk according to Example 3 of this invention.
  • ⁇ Hc/Hc was observed with respect to Comparative Example 1 shown in FIG. 5 , (a) and it was 0.26.
  • ⁇ Hc/Hc with respect to Example 3 shown in FIG. 5 , (b) was reduced to 0.15 and it has been found that the dispersion of coercive force of the magnetic grains can be reduced by forming the spacer layer 6 and the stacked layer 7 . It is considered that this caused the SN to be excellent.
  • FIG. 1 is an exemplary sectional view of a perpendicular magnetic recording disk according to one embodiment of this invention.
  • FIG. 2 is a diagram showing a magnetization reversal nucleus producing magnetic field (Hn) and a saturation magnetic field (Hs) in an MH curve.
  • FIG. 3 is a diagram of MH curves in examples and a comparative example.
  • FIG. 4 is a diagram showing a relationship between an elapsed time and a ratio to a reproduction output immediately after recording.
  • FIG. 5 is diagrams describing minor loops and hysteresis curves of a magnetic disk of a comparative example and a magnetic disk according to this invention.
  • FIG. 6 is a diagram showing a relationship between a coercive force Hc and a SNR when increasing the amount of SiO 2 .

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US9382496B1 (en) 2013-12-19 2016-07-05 Western Digital Technologies, Inc. Lubricants with high thermal stability for heat-assisted magnetic recording
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US9406329B1 (en) 2015-11-30 2016-08-02 WD Media, LLC HAMR media structure with intermediate layer underlying a magnetic recording layer having multiple sublayers
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US10083715B2 (en) 2010-05-28 2018-09-25 WD Media (Singapore) Pte.Ltd. Method of manufacturing a perpendicular magnetic disc
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US10236026B1 (en) 2015-11-06 2019-03-19 WD Media, LLC Thermal barrier layers and seed layers for control of thermal and structural properties of HAMR media
US11074934B1 (en) 2015-09-25 2021-07-27 Western Digital Technologies, Inc. Heat assisted magnetic recording (HAMR) media with Curie temperature reduction layer

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7641989B2 (en) * 2004-12-13 2010-01-05 Hitachi Global Storage Technologies Netherlands B.V. Perpendicular magnetic recording medium for high density recording and manufacturing of the same
JPWO2007116813A1 (ja) * 2006-03-30 2009-08-20 Hoya株式会社 垂直磁気記録ディスクの製造方法及び垂直磁気記録ディスク
JP4628294B2 (ja) * 2006-03-30 2011-02-09 ヒタチグローバルストレージテクノロジーズネザーランドビーブイ 磁気記憶装置
WO2007114400A1 (ja) * 2006-03-31 2007-10-11 Hoya Corporation 垂直磁気記録媒体の製造方法
US9978413B2 (en) 2006-06-17 2018-05-22 Dieter Suess Multilayer exchange spring recording media
JP2008090913A (ja) * 2006-09-29 2008-04-17 Hoya Corp 磁気記録媒体
WO2008126133A1 (ja) * 2007-03-19 2008-10-23 Fujitsu Limited 垂直磁気記録媒体
DE102007016917B4 (de) 2007-04-05 2009-12-17 Phoenix Contact Gmbh & Co. Kg Verfahren sowie System zur sicheren Übertragung von zyklischen zu übertragenden Prozessdaten
JP2008293552A (ja) * 2007-05-22 2008-12-04 Fujitsu Ltd 基板、磁気記録媒体及びその製造方法、並びに磁気記憶装置
JP2010086567A (ja) * 2008-09-29 2010-04-15 Hoya Corp 垂直磁気記録媒体の評価方法
JP5807944B2 (ja) * 2010-06-22 2015-11-10 ダブリュディ・メディア・シンガポール・プライベートリミテッド 垂直磁気記録媒体の製造方法
US8404368B2 (en) * 2010-07-30 2013-03-26 Seagate Technology Llc Multi-layer stack adjacent to granular layer
TWI702294B (zh) * 2018-07-31 2020-08-21 日商田中貴金屬工業股份有限公司 磁氣記錄媒體用濺鍍靶

Citations (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20010051287A1 (en) 2000-06-12 2001-12-13 Akira Kikitsu Magnetic recording medium and magnetic recording apparatus
US20020012816A1 (en) 2000-03-28 2002-01-31 Kenji Shimizu Magnetic recording medium
JP2002092865A (ja) 2000-09-11 2002-03-29 Hoya Corp 垂直磁気記録媒体
US6468670B1 (en) * 2000-01-19 2002-10-22 International Business Machines Corporation Magnetic recording disk with composite perpendicular recording layer
US20030017364A1 (en) * 2001-06-29 2003-01-23 Kabushiki Kaisha Toshiba Magnetic recording medium, magnetic recording apparatus and magnetic recording method
US20030064249A1 (en) * 2001-08-31 2003-04-03 Fuji Electric Co., Ltd. Perpendicular magnetic recording medium and a method of manufacturing the same
US6562481B1 (en) * 1999-03-23 2003-05-13 Fujitsu Limited Magnetic storage medium
JP2003272121A (ja) 2002-03-13 2003-09-26 Fuji Photo Film Co Ltd 磁気記録媒体
US20030219627A1 (en) 2002-03-26 2003-11-27 Showa Denko K.K. Magnetic recording medium, production process thereof, and magnetic recording and reproducing apparatus
US20040058197A1 (en) * 2000-07-19 2004-03-25 Kabushiki Kaisha Toshiba Perpendicular magnetic recording medium and magnetic recording apparatus
US20040110034A1 (en) 2002-09-04 2004-06-10 Fuji Electric Co., Ltd. Perpendicular magnetic recording medium and method of manufacturing the same
JP2004192711A (ja) 2002-12-10 2004-07-08 Fuji Photo Film Co Ltd 磁気記録媒体
US6777112B1 (en) * 2000-10-10 2004-08-17 Seagate Technology Llc Stabilized recording media including coupled discontinuous and continuous magnetic layers
WO2004090874A1 (en) 2003-04-07 2004-10-21 Showa Denko K. K. Magnetic recording medium, method for producing thereof, and magnetic recording and reproducing apparatus.
JP2004310910A (ja) 2003-04-07 2004-11-04 Showa Denko Kk 磁気記録媒体、その製造方法および磁気記録再生装置
US6881497B2 (en) * 2001-06-04 2005-04-19 Hitachi Global Storage Technologies Netherlands B.V. ‘Thermal spring’ magnetic recording media for writing using magnetic and thermal gradients
US20060134467A1 (en) * 2003-03-28 2006-06-22 Yoshiyuki Hirayama Perpendicular magnetic recording medium and method of manufacturing it
US7081268B2 (en) * 2003-06-03 2006-07-25 Seagate Technology Llc In-situ post-deposition oxidation treatment for improved magnetic recording media
US7132176B2 (en) * 2002-07-25 2006-11-07 Kabushiki Kaisha Toshiba Perpendicular magnetic recording medium and magnetic recording/reproduction apparatus
US7235314B2 (en) * 2004-03-11 2007-06-26 Seagate Technology Llc Inter layers for perpendicular recording media
US7311983B2 (en) * 2004-01-08 2007-12-25 Fuji Electric Device Technology Co., Ltd. Perpendicular magnetic recording medium and a method for manufacturing the same

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2003A (en) * 1841-03-12 Improvement in horizontal windivhlls
JP4127775B2 (ja) * 2002-07-12 2008-07-30 昭和電工株式会社 磁気記録媒体、その製造方法、および磁気記録再生装置
JP2004178748A (ja) * 2002-11-28 2004-06-24 Toshiba Corp 垂直磁気記録媒体、その製造方法、及び磁気記録再生装置

Patent Citations (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6562481B1 (en) * 1999-03-23 2003-05-13 Fujitsu Limited Magnetic storage medium
US6468670B1 (en) * 2000-01-19 2002-10-22 International Business Machines Corporation Magnetic recording disk with composite perpendicular recording layer
US20020012816A1 (en) 2000-03-28 2002-01-31 Kenji Shimizu Magnetic recording medium
US20010051287A1 (en) 2000-06-12 2001-12-13 Akira Kikitsu Magnetic recording medium and magnetic recording apparatus
US6830824B2 (en) * 2000-06-12 2004-12-14 Kabushiki Kaisha Toshiba Magnetic recording medium with multiple magnetic layers capable of being exchange coupled at elevated temperatures and magnetic recording apparatus
US20040058197A1 (en) * 2000-07-19 2004-03-25 Kabushiki Kaisha Toshiba Perpendicular magnetic recording medium and magnetic recording apparatus
JP2002092865A (ja) 2000-09-11 2002-03-29 Hoya Corp 垂直磁気記録媒体
US6777112B1 (en) * 2000-10-10 2004-08-17 Seagate Technology Llc Stabilized recording media including coupled discontinuous and continuous magnetic layers
US6881497B2 (en) * 2001-06-04 2005-04-19 Hitachi Global Storage Technologies Netherlands B.V. ‘Thermal spring’ magnetic recording media for writing using magnetic and thermal gradients
US20030017364A1 (en) * 2001-06-29 2003-01-23 Kabushiki Kaisha Toshiba Magnetic recording medium, magnetic recording apparatus and magnetic recording method
US20030064249A1 (en) * 2001-08-31 2003-04-03 Fuji Electric Co., Ltd. Perpendicular magnetic recording medium and a method of manufacturing the same
JP2003272121A (ja) 2002-03-13 2003-09-26 Fuji Photo Film Co Ltd 磁気記録媒体
US20030219627A1 (en) 2002-03-26 2003-11-27 Showa Denko K.K. Magnetic recording medium, production process thereof, and magnetic recording and reproducing apparatus
US7132176B2 (en) * 2002-07-25 2006-11-07 Kabushiki Kaisha Toshiba Perpendicular magnetic recording medium and magnetic recording/reproduction apparatus
US20040110034A1 (en) 2002-09-04 2004-06-10 Fuji Electric Co., Ltd. Perpendicular magnetic recording medium and method of manufacturing the same
JP2004192711A (ja) 2002-12-10 2004-07-08 Fuji Photo Film Co Ltd 磁気記録媒体
US20060134467A1 (en) * 2003-03-28 2006-06-22 Yoshiyuki Hirayama Perpendicular magnetic recording medium and method of manufacturing it
WO2004090874A1 (en) 2003-04-07 2004-10-21 Showa Denko K. K. Magnetic recording medium, method for producing thereof, and magnetic recording and reproducing apparatus.
JP2004310910A (ja) 2003-04-07 2004-11-04 Showa Denko Kk 磁気記録媒体、その製造方法および磁気記録再生装置
US7470474B2 (en) * 2003-04-07 2008-12-30 Kabushiki Kaisha Toshiba Magnetic recording medium, production process thereof, and magnetic recording and reproducing apparatus including both oxide and non-oxide perpendicular magnetic layers
US7081268B2 (en) * 2003-06-03 2006-07-25 Seagate Technology Llc In-situ post-deposition oxidation treatment for improved magnetic recording media
US7311983B2 (en) * 2004-01-08 2007-12-25 Fuji Electric Device Technology Co., Ltd. Perpendicular magnetic recording medium and a method for manufacturing the same
US7235314B2 (en) * 2004-03-11 2007-06-26 Seagate Technology Llc Inter layers for perpendicular recording media

Non-Patent Citations (22)

* Cited by examiner, † Cited by third party
Title
EP Search Report dated Sep. 26, 2007 from EP Patent Application No. 05765413.9, 3 pages.
European Office Action dated Jul. 25, 2008.
Examination Report for Singapore Patent Application No. 200904258-1 dated Jun. 29, 2012, 11 pages.
H. Muraoka, "Migration Pathway to Next Generation Perpendicular Magnetic Recording", Article for the 135th Topical Symposium of the Magnetic Society of Japan, Mar. 12, 2004.
Office Action dated Apr. 30, 2010 from Philippines Application No. 12006502611, 1 page.
Office Action dated Aug. 31, 2012 from CN Patent Application No. 201010002057.7, 9 pages.
Office Action dated Dec. 15, 2011 from EP Patent Application No. 05765413.9, 4 pages.
Office Action dated Dec. 21, 2010 from CN Patent Application No. 201010002057.7, 7 pages.
Office Action dated Feb. 17, 2009 from EP Patent Application No. 05765413.9, 2 pages.
Office Action dated Jan. 19, 2010 from EP Patent Application No. 05765413.9, 2 pages.
Office Action dated Jan. 3, 2008 from EP Patent Application No. 05765413.9, 4 pages.
Office Action dated Jul. 25, 2008 from EP Patent Application No. 05765413.9, 3 pages.
Office Action dated Jul. 28, 2011 from EP Patent Application No. 05765413.9, 3 pages.
Office Action dated Jul. 9, 2009 from EP Patent Application No. 05765413.9, 2 pages.
Office Action dated Jun. 15, 2010 from EP Patent Application No. 05765413.9, 4 pages.
Office Action dated Mar. 21, 2012 from CN Patent Application No. 201010002057.7, 9 pages.
Office Action dated Nov. 30, 2010 in Japanese Patent Application No. 2006-528738, 6 pages.
Office Action dated Oct. 1, 2011 from EP Patent Application No. 05765413.9, 4 pages.
S. Takenoirj, et al., "Development and Issue of CoPtCr-SiO2 Perpendicular Recording Media", Article for the 135th Topical Symposium of the Magnetic Society of Japan, Mar. 12, 2004.
T. Oikawa, et al., "Microstructure and Magnetic Properties of CoPtCr-SiO2 Perpendicular Recording Media", IEEE Transactions on Magnetics vol. 38, No. 5, Sep. 2002, pp. 1976-1978.
Y. Sonobe, et al., "Thermal Stability and SNR of Coupled Granular/Continuous Media", IEEE Transactions on Magnetics vol. 37, No. 4, Jul. 2001, pp. 1667-1670.
Y. Sonobe, et al., "Thermally Stable CGC Perpendicular Recording Media With Pt-Rich CoPtCr and Thin Pt Layers", IEEE Transactions on Magnetics, vol. 38, No. 5, Sep. 2002, pp. 2006-2011.

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US20070148499A1 (en) 2007-06-28
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CN101777354A (zh) 2010-07-14

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